This invention relates to optical fiber distribution flames.
Optical fiber distribution frames, such as AT&T's lightguide cross-connect (LGX.RTM.) distribution frame, serve the function of coupling incoming fiber optic cables to customer equipment. The frame typically includes a multiplicity of shelves, each shelf including a single or plurality of modules where the optical connections are made to the fibers of the incoming cable. Cross-connect jumper cables (also known as patch cords) are applied in the front of the apparatus between the modules which are to be optically connected (see, e.g., U.S. Pat. No. 4,630,886 issued to Laurielip et at.).
One of the problems which exists in typical frames is the high density of optical connections, typically 72-144 connections per shelf. The great number of cross-connections makes it very difficult to be able to determine if both ends of a patch connection are properly connected.
It is desirable, therefore, to test the connections of the jumper cables as well as to test for any fiber breaks. It is known to launch test signals in order to determine the condition of fibers in an optical fiber transmission system (see, e.g., U.S. Pat. No. 5,285,305 issued to Cohen et al.). However, in present frames, it is not generally practical or cost effective to test patch cords.